hdf5doc

Purpose:  Bugfix.  Four misplaced and two wrongly-described functions.
Description:
    These changes correct the following errors:
    H5Pset/get_multi_type were listed in the H5P functions index under both 
        file access and dataset access property functions.  
    H5Pset/get_small_data_block_size were listed under dataset access 
        property functions.  
    All four functions belong only among the file access property functions.
    H5Pset/get_multi_type were also described as modifying both the data 
        access property list (wrong) and file access property list (correct).
Tested:
    Firefox